For the purpose of improving the low-temperature fixing ability, which is one of the major problems to be solved in electrophotography, a resin binder for a toner, comprising a crystalline polyester has been studied (Japanese Patent Laid-Open No. 2001-222138).
However, properties which are usually incompatible with low-temperature fixing ability need to be further improved, for instance, storage ability and durability. As an example of the durability, in the case of a two-component development, the prevention of toner spent to a carrier is desired, and in the case of a mono-component development, the prevention of fusion to a blade is desired.